Improvement of the resonance ionization mass spectrometer performance for precise isotope analysis of krypton and xenon at the ppt level in argon

Resonance ionization mass spectrometry (RIMS) is an effective method for the isotope analysis of trace elements in terms of its insensitivity to isobaric interferences. In view of this advantage, RIMS has been proposed for application to the failed fuel detection and location (FFDL) system of the fast reactor. The principle of the FFDL technique using RIMS involves the isotope analysis of krypton (Kr) and xenon (Xe) with concentrations as low as parts-per-trillion (ppt) in argon (Ar). The precise detection of Kr and Xe isotopes at such low concentrations level is often difficult because of the existence of Ar+ and Ar2+ ions caused by photoelectrons generated in the vacuum chamber. We show that using both a combination of a neutralization apparatus and a Brewster window, and an electrode with a slit in the ion acceleration region of the time-of-flight mass spectrometer (TOF-MS), helps decrease the effect of Ar+ and Ar2+ ions, giving improved reliability of the FFDL system using RIMS.

Graphical abstractAn electrode with a slit was applied to limit the Ar+ and Ar2+ ions reaching the detector without loss of the Kr+ and Xe+ ion signals.Figure optionsDownload full-size imageDownload high-quality image (30 K)Download as PowerPoint slide